Part II will have three different arms; patients will receive ATH008 cream 3%, 8% or placebo in repeated doses (four times per day) since appearance of PPES grade 1 until appearance of grade 2-3 or a maximum of 4 cycles. Patients will continue to be assessed for safety. The clinical signs will be reported by iconographic register of lesions and pain will be evaluated using a pain scale. Patient will fill a questionnaire reporting QoL.